U.S. Pat. No. 3,622,026 illustrates a device for tilting a load from a vertical to a horizontal position onto the flatbed of a truck utilizing two linkages that simply rotate the load about a fixed pivot point. This is distinct from the present invention, which uses a set of driving links and another set of driven links to lift, as well as rotate, the load into a substantially horizontal storage position.
U.S. Pat. Nos. 3,627,158, 3,807,592 and US Pub. No. 20080069675 indicate apparatus which could be used for loading a wheelchair by manually tilting and lifting a rack to the level of the rear compartment of a vehicle, and then sliding or rolling the apparatus into the rear compartment. None of these loaders uses a linkage or electric motor-driven power train as does the present invention. In addition, the U.S. Pat. No. 3,807,592 requires a roller to be mounted on the rear bumper of the vehicle, and thus the apparatus is not fully contained in the rear compartment.
U.S. Pat. Nos. 4,236,860 and 4,272,218 describe apparatus for externally loading a wheelchair on the vehicle roof, rather than into a limited internal space as does the present invention. U.S. Pat. No. 4,407,624 shows a wheelchair loading apparatus having a linkage comprised of five pivotal interconnected links to raise a wheelchair into a vehicle. The wheelchair is always maintained in an upright position. The present invention stores the wheelchair in a collapsed, horizontal position, thus permitting it to be stored in a much smaller space than does the apparatus disclosed in the U.S. Pat. No. 4,407,624.
U.S. Pat. Nos. 4,573,854 and 4,616,972 propose an apparatus for loading a wheelchair or similar object, having a linkage set and a carriage. Such that the linkages elevate the object and pivot it in a horizontal angle in a forward cycle. However this design needs additional sliding tracks to bring up the horizontal stroke in order to fully retract the object into the vehicle compartment and store in a forwardmost position, while the linkage mechanism in the present invention automatically generates a comparatively longer stroke, hence requiring no track on vehicle chassis
US Pub. No. 20050105994 presents an inside-vehicle lift for transferring a load through a rear door opening of a vehicle. The load platform is horizontally movable between a loading position with the load platform being disposed behind a rear bumper of the vehicle and a transport position inside the vehicle. Multiple sets of actuators, the lift actuators and the horizontal sliding/rotating actuators, are required in US Pub. No. 20050105994 however the present invention needs only one/one set of actuator(s) to achieve the vertical lift motion as well as the horizontal sliding motion.